Chapter 6 : Models of Process Variations in Device and Interconnect

Variation is the deviation from intended or designed values for a structure or circuit parameter of concern. The electrical performance of microprocessors or other integrated circuits are impacted by two sources of variation. Environmental factors are those which arise during the operation of a circuit, and include variations in power supply, switching activity, and temperature of the chip or across the chip. Physical factors during manufacture result in structural device and interconnect variations which are essentially permanent. These variations arise due to processing and masking limitations, and result in random or spatially varying deviations from designed parameter values. in this chapter we will focus on parametric variation due to continuously varying structural or electrical parameters, as these can signi cantly impact not only yield but also performance in high speed microprocessor and other digital circuits. Such parametric variation is becoming a larger concern, as variation and margins for device and